linux-kernel - Re: [PATCH 01/28] dmaengine: use DMA_COMPLETE for dma completion status

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Message-ID: <20131025054321.GD21230@intel.com>
Date:	Fri, 25 Oct 2013 11:13:21 +0530
From:	Vinod Koul <vinod.koul@...el.com>
To:	Guennadi Liakhovetski <g.liakhovetski@....de>
Cc:	Sebastian Andrzej Siewior <sebastian@...akpoint.cc>,
	Dan Williams <dan.j.williams@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	linux-arm-kernel@...ts.infradead.org, linux@....linux.org.uk
Subject: Re: [PATCH 01/28] dmaengine: use DMA_COMPLETE for dma completion
 status

On Fri, Oct 25, 2013 at 08:32:12AM +0200, Guennadi Liakhovetski wrote:
> Hi Vinod
> 
> On Fri, 25 Oct 2013, Vinod Koul wrote:
> 
> > On Thu, Oct 24, 2013 at 11:28:29PM +0200, Guennadi Liakhovetski wrote:
> > > Hi Vinod
> > > 
> > > On Thu, 17 Oct 2013, Vinod Koul wrote:
> > > > Yes i missed it in first place update the patch to fix that
> > > 
> > > Are you planning to post a fixed version of this patch or you just fix it 
> > > internally? Would be good to have it posted to be able to ack it and other 
> > > relevant patches.
> > looks like you missed it... I had posted updated patch [1] in this thread here
> > and I posted 29th patch as removal one [2]
> 
> No, I didn't miss those, but as Sebastian pointed out and as I commented 
> too, also that v2 version wasn't correct, so, a fixed v3 was needed. 
> Consider this:
> 
> In patch 1 you do:
> 
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 0bc7275..683c380 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -45,16 +45,17 @@ static inline int dma_submit_error(dma_cookie_t cookie)
>  
>  /**
>   * enum dma_status - DMA transaction status
> - * @DMA_SUCCESS: transaction completed successfully
> + * @DMA_COMPLETE: transaction completed
>   * @DMA_IN_PROGRESS: transaction not yet processed
>   * @DMA_PAUSED: transaction is paused
>   * @DMA_ERROR: transaction failed
>   */
>  enum dma_status {
> -	DMA_SUCCESS,
> +	DMA_COMPLETE,
>  	DMA_IN_PROGRESS,
>  	DMA_PAUSED,
>  	DMA_ERROR,
> +	DMA_SUCCESS,
>  };
>  
>  /**
> 
> and then in a couple of places
> 
> -			return DMA_SUCCESS;
> +			return DMA_COMPLETE;
> 
> So, after that your patch dmaengine would be returning DMA_COMPLETE in 
> case of success, i.e. 0. But all the DMAC and user drivers would still be 
> checking for
> 
> 	if (status != DMA_COMPLETE) {
> 
> i.e. comparing status with 4 and thus detecting false errors, until your 
> further 28 patches fix them. That's why, as Sebastian pointed out it was 
> important to define DMA_COMPLETE and DMA_SUCCESS with the _same_ numerical 
> value in your patch 1.
Sure, I will fix this up now as suggested

  enum dma_status {
 -	DMA_SUCCESS,
 +	DMA_COMPLETE = 0, DMA_SUCCESS = 0,

Thanks for poiting out.

--
~Vinod
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